Packing for pistons and piston-valves.



No. 759,581. PATENTED MAY. 10, 1904. J. T. WILSON. PACKING FOR PISTONSAND PISTON VALVES.

APPLICATION rum) NOV. 19 ,1902.

no uonnn H V Y m Patented May 10, 1904.

UNITED STATES PATENT OFFICE.

JOHN T. WILSON, ()F JERSEY SHORE, PENNSYLVANIA.

PACKING FOR PISTONS AND PISTON-VALVES.

SPECIFICATION forming part of Letters Patent N0. 759,581, dated May 10,1904.

Application filed November 19,1902. Serial No. 131,938. (No model.)

To all whom it may concern:

Be it known that I, J OHN '1. WILSON, a citizen of the United States,residing at Jersey Shore, in the county of Lycomiug and State ofPennsylvania, have invented new and useful Improvements in Packing forPistons and Piston -Valves, of which the following is a specification.

The object of my invention is the production of a packing for pistons,and especially for piston-valves, which shall not press excessivelyagainst the valve-chamber, which shall be adapted to contract underexcessive portpressure, which shall be so constructed that thepackingrings will be prevented from wearing laterally, which shall becontrolled by motive-fluid pressure when the engine is workingpositively, which shall not become deranged or its efliciency beimpaired by water working through the cylinder, and which withal shallconstitute a superior means for performing the requisite functions.

My invention consists in certain novelties of construction andcombinations of parts hereinafter set forth and claimed The accompanyingdrawings illustrate one example of the physical embodiment of myinvention constructed according to the best mode I have so far devisedfor the practical application of the principle.

Figure l is a sectional View of one-half of a piston-valve, showing thepacking in position. Fig. 2 illustrates the lap-joint of the snap orpacking ring. Figs. 3 and 4 show the formation of the wedge-ringlap-joint.

Referring to the several figures, the letter A designates thevalve-spool; B, a circumferential flange with a perpendicular wall; G,

passages for water fluid; D, a hole for the valve-stem; E, afollower-plate with a flange which "has a perpendicular wall; F,threaded studs for securing the follower-plate to the spool; Gr, snap orpacking rings; H, the beveled surfaces of the snap-rings; I, flanges atthe outer terminations of the beveled surfaces; J, the free meeting endsof the snap-ring; K, the joint-plate; L, a flange with a beveledsurface; M, seats in the inner surfaces of the ends of the ring toreceive the joint-plate; N, seats with beveled surfaces in the sides ofthe ends of the ring to receive the flange L of the plate; 0, rivetswhich secure one end of the joint-plate to one end of the snap-ring; P,the Wall-rings, each made integral and having beveled sides Q and R, asshown; S, recesses in the edges of the rings to receive the flanges I ofthe snap-rings; T, the wedge-ring with beveled sides; U, the free endsof the wedge-ring; V, the joint-plate with beveled edges, which platefits seats formed in the under surfaces at the free ends of thewedge-ring, and WV is one of the rivets which secures one end of thejoint-plate to one end of the wedge-ring.

The operation of the packing in service is as follows: When motive fluidis admitted whereverthe valve is used, it passes through the openings 0to a position beneath the packing as a whole and acts simultaneously toexpand the snap or packing and the wedge rings only. The wall-rings Pbeing integral cannot expand. As the rings G expand so that their outersurfaces press against the surface of the valve-chamber the wedge-ringT, also expanding, moves the wall-rings against the snaprings, thebeveled surfaces R thereof engaging the beveled surfaces H of thesnap-rings. It will be observed that the beveled surface H of thesnap-ring inclines outwardly and is matched by the surface R of thewall-ring, which is beveled inwardly. The snap-ring consequently actslike a wedge, with its head facing toward the center of the ring. As-thesnap-ring is gripped between the wall of the spool or follower-plate andthe wall-ring it is held with its outer surface in contact with theinner surface of the valve-chamber under a limited and substantiallyuniform pressure. Motive fluid acting upon its inner surface cannotexcessively expand it, and normally the outward pressure of the motivefluid in the cylinder by way of the ports is balanced by the pressureupon the inner surface. However, where there is an excessiveport-pressure of steam or water the snap-ring can contract and relievethe same. To restore the snap ring to its normal position, the motivefluid must be shut off, as is obvious, and thereafter admitted. When theengine is drifting with do not press against the surface of thevalvechamber excessively, and consequently air under compression by theaction of the piston can pass between the packing and the valvechamberwhen it becomes excessive. The relative degrees of taper of the severalrings must, of course, in any given case be determined by experiment,but in no instance should the arrangement be such that full pressureupon the wedge-ring will cause the excessive contraction of thesnap-ring when motive fluid is acting upon its inner surface. The degreeof taper upon the snap-ring should, however, be suflicient to overcomethe action of the wedgering and allow the motive fluid to hold theformer against the surface of the valve-chamber.

From the foregoing description, taken in connection with the drawings,it is clear that I have produced a packing for a piston or piston-valvewhich fulfils all the conditions set forth as the object of myinvention.

In practice the shape and form of the several elements comprising thepacking may obviously be changed and the invention embodied by othermodes and in other examples, and one wedge-ring, one wall-ring withoutconstituting substantial departures.

What I claim as new, and desire to secure by Letters Patent, is-

1. A packing for a piston or piston-valve having two snap-rings, twowall-rings, and a wedge-ring having a beveled surface; all the ringsbeing so disposed as to receive fluid under pressure.

2. A packing for a piston or piston-valve having two snap-rings, twowall-rings, and a wedge-ring with two beveled surfaces; motive fluidbeing admitted to the inner surfaces of all the said rings.

3. A packing for a piston or piston-valve having two snap-rings, twointegral wall-rings, and a wedge-ring with a beveled surface; all therings being subjected to fluid-pressure.

4:. A packing for a piston or piston-valve havingtwo snap-rings, twointegral wall-rings, and a wedge-ring with two beveled surfaces; motivefluid being admitted to the inner surfaces of all the rings.

5. A packing for a piston or piston-valve having two snap-rings eachwith a beveled surface, two wall-rings with beveled sides; and awedge-ring engaging the wall-rings.

6. A packing for a piston or piston-valve having five rings, three ofthem being expansible and two non-expansible; all of said expansiblerings being open or exposed to fluid under pressure.

7 A packing for a piston'or piston-valve having five rings, two of thembeing non-expansible and three expansible, and one of'said expansiblerings being a wedge-ring, all the rings being subjected tofluid-pressure.

8. A packing for a piston or piston-valve having two non-expansiblerings, and three expansible rings; each of said rings having a beveledside, and one of said expansible rings being exposed to fluid underpressure.

9. A packing for a piston or piston-valve having an expansiblewedge-ring, two non-ex: panslble rings, and two expans1blesnap-r1ngs;

each of said expansible or snap rings having one side beveled, and eachof said non-expansible rings having two sides beveled.

In testimony whereof I affix my signature in presence of two witnesses.

JOHN T. INILSON.

Witnesses:

RoB'r. A. SEEKING, WM. R. PEOPLES.

